Timing regulators



Feb. 2, 1965 G. I. FREDHOLM 3,168,739

TIMING REGULATORS .Eiled Feb. 25, 1960 6 Sheets-Sheet 1 Feb. 2, 1965 G. 1. FREDHOLM 3,168,739

TIMING REGULATORS Filed Feb. 25, 1960 6 Sheets-Sheet 2 Feb. 2, 1965 G. l. FREDHOLM 3,168,739

- TIMING REGULATORS Filed Feb. 25, 1960 6 Sheets-Sheet 3 G. l. FREDHOLM TIMING REGULATORS 6 Sheets-Sheet 5 Feb. 2, 1965 Filed Feb. 25, 1960 Feb. 1965 s. l. FREDHOLM 3,158,739 TIMING REGULATORS Filed Feb. 25, 1960 6 Sheets-Sheet 6 United States Patent TIMING REGULATORS Gunnar Ivar Fredholm, Forfattarvagen 44, Bromma, Sweden Filed Feb. 25, 1969, Ser. No. 10,905 Claims priority, application Sweden, Mar. 5, 1959,

7 Ciaims. (Cl. 346-74) This invention relates to timing devices for the control of certain defined junctures, for instance diiierent steps in a courseor measures or manoeuvres in a series of such courses' i Bymeans of the device according to the invention it is possible in the first place to divide an arbitrary period of time up into a number of intervals of certain determined difterent lengths or, secondly, to divide an arbitrary length in a certain defined manner. As practical applications according to the invention may be mentioned cutting or folding of material lengths, measuring of the average speed along a certain part of a track, control of certain variation of temperature, pressure, velocity, charging of articles or raw materials into machines or apparatuses for subsequent treatment of these articles, successive reading of instruments and gauges at different time intervals, or the like.

. Broadly the invention pertains to the storing upon a conveyor running at a constant transport speed of markings from one or more time defining members after transport over a defined length. The markings or recordings may be obtained by means of magnetic or visible marks, or by means of bodies which may be transferredtothe above mentioned conveyor at a certain junction under the control of the time defining members. In the latter case balls, members or elements attached by hooks, magnetic bodies, slides or such like may be used.

In the drawings:

FIG, 1 gives in a side view the principle of a timing regulator consisting of a system of endless conveyors driven at different speeds.

FIG. 2 is an end view of the same device.

FIG. 3 shows in a side view the principle of a timing device having circular conveyor paths.

FIG. 4 is an axial section of the same device. f

FIG. 5 shows a wiring diagram of a servo-mechanism.

FIG. 6 is an axial section through a timing regulator based upon the principle visualized in FIGS. 3 and 4.

FIG. 7 is a section along the 7-7 line in FIG. 6.

FIGS. 8 and 9 show a detail arrangement seen in two different directions at right angles to each other.

Referring to FIGS. 1 and 2 a timing regulator arranged with endless strips is described below.

A regulator strip 1 runs on two rollers 2 and 3 at constant velocity. A further number of endless tapes or strips 4, 5, 6 each defined for its special time interval, and running on pulleys, are arranged to cooperate with strip 1. This latter strip is given two head marks, H and H situated from one another at a distance A, which corresponds to the magnitude which is to be divided up into sections. In order that the description may be simplified, it is assumed that the magnitude in question represents a time interval, within which certain defined junctures are to be determined. Hereby the strips 4, 5 and 6 are given different velocities proportioned according to the length of time intervals.

Thus, if the time period A is to be divided up, for instance, into four equal parts, the strips 4, 5, 6 are given velocities proportional to A/4, 2A/4 and 3A/4 respectively.

According to a chosen example all the tapes orstr-ips may be of magnetic material, which makes possible mag netic marking and erasing.

3,lfi8,?39 Patented Feb. 2, 1965 When the head mark H passes a start point S for the course, the marks P P and P are transferred to the strips 4, 5 and 6 by the aid of a pick-up magnet R situated at S, and a thereto attached recording magnet M The said marks P P and P travel at different constant speeds during the movement of the strips, so that the mutual distances between them are constantly increased. The moment the head mark H passes the reading magnet R relays connect a mechanism containing two clamps 7 and 8, which during a short moment, bring the strips 4-6 to rest against strip 1, so that the magnetic marks on strips 46 are recorded on the strip 1. As will be seen from the figures, the upper part of strip 1is situated near the lower part of strips 46. The shafts for the rollers 2 and 3 and for the pulleys are parallel and rotate in the directions indicated by the arrows, so that adjacent parts of the strip group are moving in the same direction. The pulleys are suitably connected to their respective shafts by means of friction couplings, which make possible the achievement of one and the same velocity during the short moment at which the-strips are pressed together for the above transfer of marks.

In order to avoid wear at the clamps 7 and 8 against the strips, the whole clamp arrangement may be supported displaceably in the direction of the movement of the strips, so that the clamps are given the same speed as that of strip 1.

After the transfer of the recording the clamps 7 and 8 are released from the strip and the clamping device returns to its original position, eventually by the aid of a spring arrangement.

When the marks'transferred onto strip 1 are passing a pick-up magnet R electric impulses may be obtained for control of the course intended. The recordings on the strips may be eliminated by means of permanent magnets, C and D, mounted at points suitable for the purpose. It is readily appreciated that the strips 4 to 6 again are applicable and ready for the next measuring period, immediately after'th'e magnetizing of the recording magnets M at impulse from the head mark H on the pick-up magnet R Thus, one needs not await the juncture of the record transfer onto strip 1. It should be plain, that a period of the timeor a track length, according to the above principle, may be divided into sections of different lengthsall in accordance with the'proposition at hand. To the strips 410 6 may be added further'strips, or they may be replaced by a large number of magnetizeable .wires. f

According to the invention a sectional point situated at u/ v of A, where the u-value lies between zero and v, may be obtained by giving an auxiliary strip the velocity u/v, 1f the speed of the control strip is put at 1.

As stated above, the marks may be constituted by visual signs which are made readable by photocells or the like. The marks, which during the measuring procedure are transferred from one strip to another, may in this case be obtained by means'of for instance stamps, types of other rmpression members.

By application of bodies as marks conveyors of the type described above may be arranged near each other on the same level and means arranged for transferof the mark bodies from one strip to another. Electric impulsegiving contact organs are fitted in the path of the mark bodies on the conveyor. Particularly advantageous is, in this respect, the application of metal strip of paramagnetic material, for instance steel strip, in combination with mark bodies formed by small permanent magnets.

Referring to FIGS. 3 and 4 an embodiment according to the invention is described in the following, where mark bodies are applied and where the conveyor for these is constituted by circular track s. Owing to this arrangement the timing regulator may be given a compact form ,and the driving members may be'simplified. V

The main members of this embodiment consist of three circular discs, 21, 22 and 23, which are mutually concentrically supported and which may .rotatewithin a stand ring 24 concentric with the discs. The inside surface 25 of this ring is cylindrical andconcentrically arranged in relation to the discs and forms a roller track with a pollone current lead 46 and an electromagnet i'l which, in

ished and hard surface for balls 26. The discs 21, 22 and V 23 have a cylindrical circumference formed by an elastically yielding layer, having identical outer diameter for all three discs. Between'the discs and the roller traclc 25 there is a space of slightly less radial dimension thanthe diameter ofthe balls 26 so that, when-the discs rotate, the balls will roll with a certain pressure ,on the track 25, whereby sliding is prevented. The balls'm'ay be ball bearing balls of one and the same dimension.

Thediscs 21 to 23 are arranged to rotate, for exaxple through a gear, with mutually different speeds; For the disc 22 a speed of rotation is chosen which turns the disc approximately half a revolution during the course of time which is actual for the case at hand. The discs 21' 5 and 23 are driven more slowly at a speed which is proper tional to the time sections which areto be marked.

In the stand ring 24 two ball storing boxes 28 and:29 are arranged, one for each disc ,21 and 23 respectively. 'I'heseball boxes are formed aschannels havingsuch a cross sectional area that the balls can move easily. from an inlet 30 at the upper part of the'box downwards to an outlet 31. The inlet and outlet are in communication with the space between the discs and the roller track, so that the balls may roll in on this latter, and, having travelled their track length, return down into theirstoring boxes.

The outlet 31 is approaching the track tangentially, enabling the balls 26 when rolling on said track, tomove in the direction of rotation of the discs 21 and 23, as

indicated by the arrow 32. I V

The balls are retained in their storing boxes by means of an adjustable blocking disc 33 which is so arranged and designed that, when reset clock-wise half a revolution, one ball is released to roll down through the outlet 31 during which operation the remaining balls are retained in the ball box. The disc 33 is circular and mount ed on a shaft 34 and designed with 'a segmented cut-away 35 which, according to FIG. 3, is turned upwards. When the cutaway 35 is turned downwards by the turning clockwise of the disc 33,0ne ball is released, whereas the next;

ball is stopped by the circular part of the disc '33; Thus it is possible to release one ball from each ball box which balls engage the discs 21mm 23 respectively at the lower part of these discs. Said discs rotate at diiferent constant turn, is connected to the other'current lead 48. A wire 49 from the current lead .46 is connected to an electromagnet 52 by a switch 50 and a'wire 51 and theelectro magnet 52 is, in turn, connected to'thelead 48. by the .wire 53. A wire 54 connected between thewiresv wand 53, is fitted. two contactsSS in series withan electromagnet 56. The contacts '55 are arrangedjto" bej overbridged by means of the above mentioned moveabl'econtact members 4-0 and 41. W V I The electromagnet 56'is provided with a core 57 firmly connected to a latch-bolt 58 which carries a contact memfber'59 and is arranged to engage one of two notches 60 in a disc 61. This latter may be designed to have one or more such notches situated at different peripheraldis tances. According to the examplethe disc 61 is formed with two diametrically situated notches for the latch-bolt,

so that a half-revolutionmechanism is obtained. The.

disc .61 is driven by a shaft 62, which may be connected to a driven shaft 64 by means of. a friction coupling '63. This takes place under the control of the electromagnet 52. When'this is magnetized over the switch 50, the coupling 63 is brought into active position. The switch 50 is closed at the magnetizing of the electromagnet 56, whereat at the same time the latch-bolt 53 is withdrawn from the. notch 60 of the disc 61.. This takes place immediately one of the contact members 40, 41 isac'tuated by avball 26 at the upper part of the track. Hereby the disc til-is released and through'the connection of thec'ohpling 63 is brought to rotate, the mechanismbeing so designed, that the; bolt 58 rests against, the periphery of the disc 61, thereby retained in a position in which the switch 50 is kept closed. When the disc 61, according to the examples shown, has been turned half a revolution, the latch-bolt 58 engages the second notch, whereby the disc 61 is stopped. At the same time the current to the electromagnet 52 is shut off and the coupling 63 is dis connected. According to FIG. 5 the shaft 62 is provided with an excenter member 65, which acts upon an arm 67 swingably supported at 66. The arm 67 is kept in errgagement with the excenter 65by means of a spring 68.

speeds and the-balls are thus, after a certain period, situated in diiferent peripheral positions. Therefore, when the disc 22 has travelled half a turn, the balls are situated at such points onthe track as correspond to the actual time intervals. In the moment the time period,intended for division, is up, bothballs are transferred axially inwards onto the track 25 so as to engagethe disc 22 as shown in FIG; 4. This transfer of the balls is achieved by means of two ring halves 36 and 37 which, each from its side, project in between the track. 25 and the discs 21-23. In FIG. 4 are shown the ring halves in the above inserted position, where the balls are transferred to engage the disc 22. Chain-dotted lines 38 and 39 indicate the outer inoperative position of the ring halves. They move to this outer position in the moment the measuring period iscornmenced, by which the balls released from the ball bones at this moment, are allowed. to enter onto the track. During the entire measuring course the ring halves are withheld in their outer position'and are moved inwards, back into the position as shown, at the end of the measuring period. The movement of the rings may be carried The arm '67 may be used as folding arm in a folding mechanism for mangled clothes for instance, but it may also represent a motion. contraption generally, having a forward and return motion. I a a I The electromagnet47 may be used. for the manipulation of the ring halves 36 and 37 (FIGS; 3 and 4), whereby the switch 45 is intended to close at the beginning of the measuring period and to be kept closed throughout this A course.

Hereby the electromagnet 47, when energized, by the aid of a suitable mechanism moves the ring halves 36 and 37 from their inner position shown in FIG. 3 into the outer positions 38, 39 and retains them in this position, The mechanism mentioned may even serve in the angular adjustment of the blocking disc 33, so that' one ball from each ball rack 28 and 291s enabled to enter onto the track 25 for further transport during the measuring course, as has been. described above.

In FIGS. 6 and 7 a chosen timing regulator design is shown in accordance with the invention. This design is based upon the principle described in connection with FIGS. 3 to 5 and is particularly suitable in cooperation with a folding mechanism for mangled'clothes. According to theexample shown it is assumed that the'folding contraption works synchronously with the mangle, which may comprise a number of mangle rollers co-operating with ironing chests which together form the so-called mangle table over which the mangled garment are fed from the inlet of the mangle by means of the rollers over the different ironing chests and delivered to the folding contraption mounted next to the mangle.

In a machine stand cover 71 an input driving shaft 72 is arranged to be driven synchronously with the driving shaft of the mangle, suitably connected with one of the mangle rollers. The shaft is supported in two ball bearings 73, 74 and is fitted with fixed driving gear wheels 75, 76 and 77 arranged side by side. In ball bearings 78 and 79 is supported a shaft 80 which at one end is provided with a fixed gear wheel 81, which engages the gear wheel 75 on shaft 72. At its opposite end the shaft 80 is provided with a fixed cylindrical disc 82, situated near the ball bearing 79. The disc has on its cylindrical surface an elastic, Wear resistant layer 83 of even thickness. The shaft 80 is surrounded by a hollow shaft 84 which at both ends is rotatably supported on the shaft 80 by means of pin bearings 85. A gear wheel 86 is fixed onto the outer end of the shaft 84 and this wheel, which is concentric with the gear wheel 81 and situated next to this is arranged to engage the driving wheel 76. At its inner end the shaft 84 is fixed into a cylindrical disc 87, which is co-axial with the disc 82 and situated next to this. Still one more hollow shaft 88 is arranged rotatably on the shaft 84 by means of pin bearings 89. The shafts 80, 84 and 88 are mutually co-axial and mutually rotatable. The shaft 88 is provided with a fixed gear wheel 90 arranged next to the gear wheel 86 and engaging the driving wheel 77. At its other end the shaft 88 is supporting a fixed cylindrical disc 91, which is co-axial with the discs 82 and 87 and placed next to the latter disc. The discs 87 and 91 are on their cylindrical surfaces coated with a layer of elastic material of the same kind and thickness as the layer 83 on the disc 82. The discs and the layers are of such dimensions that the discs have identical outer diameters. The discs 82, 87 and 91 thus correspond to the discs 21 to 23 in FIGS. 3 and 4.

The ratios of reduction between the gear wheels 75 and 81, 76 and 86, 77 and 90 are 1:4, 1:1 and 3:4 respectively, whereby the shaft 80 is driven at 1/4, shaft 84 at 1/1 and shaft 88 at 3/4 of the rpm. of the shaft 72.

A stand ring 92, concentric with the discs 82, 87 and 91, is fixed in the cover 71. The ring has a cylindrical outer and inner surface, whereby this latter provides a cylindrical inner track 93 having a hardened and polished surface. This track is situated at a distance from the outer tracks of the discs 82, 87 and 91. The inner track 93 corresponds to the roller track 25 in FIGS. 3 and 4 and the purpose of the discs mentioned is to roll the balls on the track 93 by means of the elastic layer of the discs, whereby the distance between this layer and the track 93 is slightly less than the diameter of the balls.

The ring 92 is at each side provided with a magazine 95 for balls 94 lying in a row on a track concentric with the ring. Each ball magazine 95 is formed as a groove with rectangular cross section in the side surface of the ring. This groove is covered with a plate 96, so that a channel is formed. The release of balls from the magazines 95 is controlled by the aid of a valve contraption consisting of a turnably supported shaft 97 projecting axially through the ring 92 and partly through the ball magazines. At each ball magazine the shaft 97 is provided with a notch 98, which is so designed that, when turning the shaft approximately 60 from an original position, one ball is released from each of the magazines, whereas the remaining balls are retained. The release ball rolls downwards to the track 93. When the shaft 97 is turned back into its starting position, the ball next in turn in the magazine is caught in the notch 98.

At the upper part of the track 93 two contact arms 100 and 101 are mounted. These arms extend into the space between the disc 87 and the track 93 from each side of the ring 92. The contact arms, moreover, are connected to the control shaft of switches 102 which are connected in a circuit for the control of the folding mechanism.

The above valve contraption, the shaft 97, is at its one end fixed to a control lever 103 which is forked at its outer end and arranged to engage a pin 104 on a control ring 105. This latter ring surrounds the stationary ring 92 and is turnably mounted onto this by means of balls 106, 107. The balls roll on the outer surface of the ring 92 and in concentric grooves 108 of the ring 105. This ring is turnable between two end'positions, situated at such a distance from each other that the control lever 103 may be turned downwards in an angle approximately 60 from the position shown in FIG. 7. v

By means of an upwards projecting link rod 110 the control ring 105 is connected with the core 111 of a. pulling electromagnet 112 mounted in a carrier 113 which is fixed onto the cover 71. The'lower .end of the link rod is connected to the ring 105 by a pin 114. At this point the ring has at its circumference a peripherally running groove 115 of such width as to receive the link I0 110.

By connecting theelectromagnet 112 into an electric circuit, the core 111 is attracted and is moved to an upper position according to FIG. 7, whereby the link rod 110 is pulled upwards and the control lever 103 is pushed upwards, due to the engagement with the pin 104, from the position shown in dotted lines to the position drawn in full.

The control ring 105 is provided with three pairs of wedgeformed elements 121, 122 and 123 spread over approximately half the circumference of the ring. In FIGS.,

8 and 9 one pair of such wedge elements is shown. Each element is screwed together with the side surface 125 of the control ring 105. The surface 126 of the wedge itself, which inclines relatively to the said side surface 125, extends to a surface 127 which is parallel to the side surface 125 of the ring 105. The Wedge bodies are formed with a radius identical to the ring 105. The purpose of the wedge elements is to shift pins 130 axially outwards relatively to the track 93 during clock-wise turning of the control ring 105 according to FIG. 7. The pins are radially fixed into ring halves 131. Each of the ring halves is supported axially moveable at each side of the ball track ring 92 and serves the same purpose as the ring halves 36 and 37 described in connection with FIGS. 3 and 4. In order to guide the ring halves 131, these are provided with three guiding rods 133 arranged at mutual peripheral distances. These rods are tube-formed and moveable in bores 134 running axially through the ring 92. At each pair of wedges 121, 122 and 123 there is a pair of the pins 130 one at each side of the ring 92. The tube-formed guide rods 133 are also arranged in pairs near the wedges elements, whereat the rods in one pair are introduced, each from its side, in a common bore 134. In this bore a spring 135 is arranged, tending to pull the two ring halves 131 towards each other. Each end part of the spring 135 is fixed onto the ring-half by a splint 136. The ring halves are provided with a cylindric flange 137 arranged to be inserted into the space between the track 93 and the discs 82, 87 and 91 for the purpose of axial movement of the balls 94 out of engagement with the discs 82 and 91 and into engagement with the disc 87. The ring halves 131 are normally situated in the above mentioned inserted position indicated by the dotted lines. The outer position shown in FIGS. 6 and 7 has been obtained by the turning clock-wise of the control ring 105 so far that the pins 130 rest against the surfaces 127 of the wedge elements. In this position balls, released from the ball magazines, may run into the track.

When the electromagnet 112 is deenergized the control ring 105 is returned to its starting position by the weight of the link rod 110 and the core 111, whereat the surfaces 127 of the wedges are brought out of engagement with the pins 130 which then engage the inclined surfaces 126. Alternatively the pins may be provided with a roller which rolls on the wedge surfaces.

The operation of the mechanism. shown in FIGS. 6 m9 is shortly as follows.

Due to a starting. impulse from the measuringdevice the electromagnet 112 isfirst magnetized, the controlring 1:95 and the control lever. 163 being turned into the position shown in full in FIGS. 6 and 7. Hereby one ball jectintended for measurement passes'over the measuring track. The .oneball thustravels a distance which, ac-

cording to theexample, is one third of the way of the other ball. Thus,when a finishing impulse i delivered from the measuring device, the electromagnet 1&2 is deenergized and the ring- 105 is turned back into its starting position whereby the ring halves 132 are pushed into.

their inner position, transferring the ballsfrom the outer tracks; to thecommon inner'track in which the central disc 87 carries the balls maintaining their thus obtained mutualperipheral distance. The halls then arrive, one after the other at the upper part of the ball track where they are met'by the contact arms 1% and 101, whereby electric impulses for the chosen time periods are obtained. The ball which has travelled the longest distance, thus arrives first at the contacts Where it influences the contact arm 191, whereby its micro switch 102 is closedand gives impulses tothat folding device or work section which is connected to the timing regulator. Thereafter the second ball arrives at its contact armliltl, whereby a starting impulse. again .is obtained for the course in question.

When theballshave passed the contact arms, they travel along and enter. a pocket 140 in the stand ring 92, wherefrom they roll downwards, each into its magazine guided by a plowshaped guide insertion 141 in the pocket mentioned.

In cases where the measuring course extend over a time period longer than that which is intended for the timing device at hand, the, rpm. of the input driving shaft 72;may.be reduced by means of an intermediate gearing. If, however, by mistake, an extended measuring period should be chosen, there is no risk of damaging the mechanism, as, in such a case, the balls carried by the discs 82 and 91 pass under bent-up parts 142 and 143 of the contact arms 100 and 101.

In both cases of design with circular tracks other marking bodies than balls may be applied throughrelatively simple alterations of the construction. For example, the

elastic layer 813 on'the circumference of the discs may be replaced by a strip of magnetic material and the balls replaced by permanent magnets in the shape of discs or'the like, which are charged from magazines, made of unmagnetic material, into contact with the magnetic disc strips. Apart from this, the design remains unaltered. The track 93 is, however, in this case superfluous.

What I claim .is:

l. A timingdevice for supervision of defined junctures, comprisingone main conveyor and at least two auxiliary conveyors, said conveyors being arranged to run at different and constant speeds side by side, the main conveyor being arranged to run at higher speed than the auxiliary conveyors, means for driving said auxiliary conveyors at predetermined and dilterent speeds, means for marking a point on each of the auxiliary conveyors at one and the same moment, means for transferring said marks toithe main conveyor after a given time period and stationary means arranged in the path of said two marks of themain conveyor adapted to be influenced by saidmarks.

2. A timing-device as claimed in claim 1, in which the conveyors are made of material adaptedfor magnetic recording. i

3. Atiming device and near. and in the same direction as one part of the main conveyor, said device further comprising clamping means arranged to press the auxiliary conveyorssduring a short time interval against the main conveyor so that magnetic recordings maybe transferred from the auxiliary conveyors to the main conveyor.

4. A timing device as claimed in claim 1 comprising means for placing a body on each of the auxiliary conveyors, means for transferring said, bodies to the main conveyor after a given time period and stationary'means.

in the pathof said bodies on the main conveyor adapted to be influenced by said bodies.

5. A timing device as claimed in claim conveyors consist of circular and coaxial discs having the same diameter and a common cylindrical surfaeewith a larger radius than the discs surrounding the same, means for placing a ball on each of the auxiliary conveyors, means for transferring said balls to the main conveyor after a given time period and stationary'means in the path of said balls on themain conveyor adapted to be influenced by said balls.

6. A timing devicefor supervision of defined junctures, comprising one main conveyor and at least two auxiliary conveyors, said conveyors being arranged town at different and constant speeds side by side, the main conveyor beingarranged to run at a higher speed than the auxiliary conveyors, means, for driving said auxiliary conveyors at predetermined and different speeds, said conveyors consisting of circular and coaxial discs having the same diameter and a common cylindrical surface with a larger radius than the discs surrounding the same, said cylindrical surface constituting the inner surface of a'ring-shaped member providing passages for balls and constituting a ball magazine, meansfor placing a ballon each of the auxiliary conveyors, means for transferring said balls to the main conveyor after a given time period and stationary means in the path of said balls on the main conveyor adapted to be influenced by said balls.

7. A timing. device as claimed in claim 6, comprising contact members for electric switches arranged: at the main conveyor to be influenced by the balls travelling on the latter said conveyor.

References Cited by the Examiner UNITED STATES PATENTS 7/59 Johnson 346+74 X 5/60 Begun et a1. 346 -474 as claimed in claim' 1, in which the auxiliary conveyors and the main conveyor consist of endless elements and pulleys ppo'rting said elements, one part of the auxiliary conveyors running parallel to l, in which said- 

1. A TIMING DEVICE FOR SUPERVISION OF DEFINED JUNCTURES, COMPRISING ONE MAIN CONVEYOR AND AT LEAST TWO AUXILIARY CONVEYORS, SAID CONVEYORS BEING ARRANGED TO RUN AT DIFFERENT AND CONSTANT SPEEDS SIDE BY SIDE, THE MAIN CONVEYOR BEING ARRANGED TO RUN AT HIGHER SPEED THAN THE AUXILIARY CONVEYORS, MEANS FOR DRIVING SAID AUXILIARY CONVEYORS AT PREDETERMINED AND DIFFERENT SPEEDS, MEANS FOR MARKING A POINT ON EACH OF THE AUXILIARY CONVEYORS AT ONE AND THE SAME MOMENT, MEANS FOR TRANSFERRING SAID MARKS TO THE MAIN CONVEYOR AFTER A GIVEN TIME PERIOD AND STATIONARY MEANS ARRANGED IN THE PATH OF SAID TWO MARKS OF THE MAIN CONVEYOR ADAPTED TO BE INFLUENCED BY SAID MARKS. 